hello :<span> <span>an equation of the circle Center at the
O(a,b) and ridus : r is :
(x-a)² +(y-b)² = r²
in this exercice : a =0 and b = 0 (Center at the origin)
r = AO
r² = (AO)²
r² = (4-0)² +(5-0)² = 16+25=41
an equation of the circle that satisfies the stated conditions.
Center at the origin, passing through B(4, 5) is : x² +y² = 41</span></span>